42,857 research outputs found
Holographic phase transition from dyons in an AdS black hole background
We construct a dyon solution for a Yang-Mills-Higgs theory in a 4 dimensional
Schwarzschild-anti-de Sitter black hole background with temperature T. We then
apply the AdS/CFT correspondence to describe the strong coupling regime of a
2+1 quantum field theory which undergoes a phase transition exhibiting the
condensation of a composite charge operator below a critical temperature .Comment: 19 pages, 7 figures. Minor corrections, references added. Version
published in JHEP
Analytic study of properties of holographic p-wave superconductors
In this paper, we analytically investigate the properties of p-wave
holographic superconductors in -Schwarzschild background by two
approaches, one based on the Sturm-Liouville eigenvalue problem and the other
based on the matching of the solutions to the field equations near the horizon
and near the asymptotic region. The relation between the critical
temperature and the charge density has been obtained and the dependence of the
expectation value of the condensation operator on the temperature has been
found. Our results are in very good agreement with the existing numerical
results. The critical exponent of the condensation also comes out to be 1/2
which is the universal value in the mean field theory.Comment: Latex, To appear in JHE
Symptomatic treatment of children with anti-NMDAR encephalitis.
Abstract
AIM:
We performed the first study on the perceived benefit and adverse effects of symptomatic management in children with anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis.
METHOD:
A retrospective chart review was undertaken at two tertiary paediatric hospitals in Australia and New Zealand. We included 27 children (12 males, 15 females; mean age at admission 7y 1mo) with anti-NMDAR antibodies in serum or cerebrospinal fluid with a typical clinical syndrome.
RESULTS:
Only two out of 27 patients were white, whereas 16 out of 27 patients were from the Pacific Islands/New Zealand Maori. The mean duration of admission was 69 days (10-224d) and 48% of patients (13/27) needed treatment in an intensive care setting. A mean of eight medications per patient was used for symptomatic management. Symptoms treated were agitation (n=25), seizures (n=24), movement disorders (n=23), sleep disruption (n=17), psychiatric symptoms (n=10), and dysautonomia (n=four). The medications used included five different benzodiazepines (n=25), seven anticonvulsants (n=25), eight sedatives and sleep medications (n=23), five antipsychotics (n=12), and five medications for movement disorders (n=10). Sedative and sleep medications other than benzodiazepines were the most effective, with a mean benefit of 67.4% per medication and a mean adverse effect-benefit ratio of 0.04 per medication. Antipsychotic drugs were used for a short duration (median 9d), and had the poorest mean benefit per medication of 35.4% and an adverse effect-benefit ratio of 2.0 per medication.
INTERPRETATION:
Long-acting benzodiazepines, anticonvulsants, and clonidine can treat multiple symptoms. Patients with anti-NMDAR encephalitis appear vulnerable to antipsychotic-related adverse effects. Pacific Islanders appear to have a vulnerability to anti-NMDAR encephalitis in our region
Genetic diversity of common toads (Bufo bufo) along the Norwegian coast : disjunct distribution of locally dominant haplotypes
Little is known about the phylogeographic history of amphibian populations along the western Fennoscandinavian coast.
In the present study, we focus on the common toad (Bufo bufo) and document the spatial distribution of mitochondrial
DNA (cytb) haplotypes at 20 localities along its coastal Norwegian range. Two common haplotypes (out of eight haplotypes
in total) were represented by 142 out of the 154 (92%) investigated individuals. However, they were shared at only three
localities and clustered at two separate geographic regions each. The most common haplotype (55% of individuals) has
previously been found to be abundant across central and eastern Europe, whereas the second most common haplotype
(37% of individuals) has so far only been recorded in Sweden. The disjunct distribution of genetic lineages is in line with an
assumption that the Norwegian coastline was postglacially colonised both from the south as well as across mountain passes
from the east. Our data support previous studies on the phylogeography of Fennoscandinavia that revealed that post-glacial
recolonisation patterns led to a pronounced spatial structure of local populations
Charged black rings in supergravity with a single non-zero gauge field
General charged black ring solution with two angular momenta, a charge and a
dipole charge is found by the inverse scattering method. The solution is
presented in a relatively concise form in which its symmetries are manifest.
The regularity conditions are found and the physical characteristics of the
regular solution are expressed via its parameters.Comment: Misprints corrected, references added, JHEP forma
Assessment of the feasibility of an ultra-low power, wireless digital patch for the continuous ambulatory monitoring of vital signs.
BACKGROUND AND OBJECTIVES: Vital signs are usually recorded at 4–8 h intervals in hospital patients, and deterioration between measurements can have serious consequences. The primary study objective was to assess agreement between a new ultra-low power, wireless and wearable surveillance system for continuous ambulatory monitoring of vital signs and a widely used clinical vital signs monitor. The secondary objective was to examine the system's ability to automatically identify and reject invalid physiological data. SETTING: Single hospital centre. PARTICIPANTS: Heart and respiratory rate were recorded over 2 h in 20 patients undergoing elective surgery and a second group of 41 patients with comorbid conditions, in the general ward. OUTCOME MEASURES: Primary outcome measures were limits of agreement and bias. The secondary outcome measure was proportion of data rejected. RESULTS: The digital patch provided reliable heart rate values in the majority of patients (about 80%) with normal sinus rhythm, and in the presence of abnormal ECG recordings (excluding aperiodic arrhythmias such as atrial fibrillation). The mean difference between systems was less than ±1 bpm in all patient groups studied. Although respiratory data were more frequently rejected as invalid because of the high sensitivity of impedance pneumography to motion artefacts, valid rates were reported for 50% of recordings with a mean difference of less than ±1 brpm compared with the bedside monitor. Correlation between systems was statistically significant (p<0.0001) for heart and respiratory rate, apart from respiratory rate in patients with atrial fibrillation (p=0.02). CONCLUSIONS: Overall agreement between digital patch and clinical monitor was satisfactory, as was the efficacy of the system for automatic rejection of invalid data. Wireless monitoring technologies, such as the one tested, may offer clinical value when implemented as part of wider hospital systems that integrate and support existing clinical protocols and workflows
Thermal Buckling and Vibration Analysis of SMA Hybrid Composite Sandwich Beams
This work studies the buckling and free vibration behavior of Shape Memory Alloy Hybrid Composite (SMAHC) sandwich beams under a thermal environment. The sandwich beams consist of layers reinforced with SMAs and a FGM core, and they are simply supported at both ends. The higher order theory is combined with the Minimum Potential Energy principle or Hamilton principle to derive the governing equations of the thermal buckling and thermal vibration problems, respectively. The material properties of the beam are assumed as temperature-independent (TID) or temperature-dependent (TD). In the last case, two different types of thermal distribution are considered, namely a uniform and a linear distribution. The results based on the proposed formulation are verified against the reference literature, with a very good matching. A parametric study checks for the influence of different effective parameters such as thickness-to-length ratios, volume fraction powers, initial strain, volume fraction of SMA wires, and temperature distribution on the overall mechanical response of the selected structural member, with useful insights from a design standpoint
Holographic Superconductors from Einstein-Maxwell-Dilaton Gravity
We construct holographic superconductors from Einstein-Maxwell-dilaton
gravity in 3+1 dimensions with two adjustable couplings and the charge
carried by the scalar field. For the values of and we
consider, there is always a critical temperature at which a second order phase
transition occurs between a hairy black hole and the AdS RN black hole in the
canonical ensemble, which can be identified with the superconducting phase
transition of the dual field theory. We calculate the electric conductivity of
the dual superconductor and find that for the values of and where
is small the dual superconductor has similar properties to the
minimal model, while for the values of and where is
large enough, the electric conductivity of the dual superconductor exhibits
novel properties at low frequencies where it shows a "Drude Peak" in the real
part of the conductivity.Comment: 25 pages, 13 figures; v2, typos corrected; v3, refs added, to appear
in JHE
A Similarity Measure for GPU Kernel Subgraph Matching
Accelerator architectures specialize in executing SIMD (single instruction,
multiple data) in lockstep. Because the majority of CUDA applications are
parallelized loops, control flow information can provide an in-depth
characterization of a kernel. CUDAflow is a tool that statically separates CUDA
binaries into basic block regions and dynamically measures instruction and
basic block frequencies. CUDAflow captures this information in a control flow
graph (CFG) and performs subgraph matching across various kernel's CFGs to gain
insights to an application's resource requirements, based on the shape and
traversal of the graph, instruction operations executed and registers
allocated, among other information. The utility of CUDAflow is demonstrated
with SHOC and Rodinia application case studies on a variety of GPU
architectures, revealing novel thread divergence characteristics that
facilitates end users, autotuners and compilers in generating high performing
code
P2X receptors: epithelial ion channels and regulators of salt and water transport.
When the results from electrophysiological studies of renal epithelial cells are combined with data from in vivo tubule microperfusion experiments and immunohistochemical surveys of the nephron, the accumulated evidence suggests that ATP-gated ion channels, P2X receptors, play a specialized role in the regulation of ion and water movement across the renal tubule and are integral to electrolyte and fluid homeostasis. In this short review, we discuss the concept of P2X receptors as regulators of salt and water salvage pathways, as well as acknowledging their accepted role as ATP-gated ion channels
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